This section introduces aspects that may help facilitate a better understanding of the disclosure. Accordingly, these statements are to be read in this light and are not to be understood as admissions about what is or is not prior art.
Due to the widespread interest in modulating graphene electronic properties, significant efforts have been directed toward ordering noncovalent ligand layers to control molecule-substrate interactions (MacLeod, J. M. et al., Small 2014, 10, 1038-1049; Mann, J. A. et al., J. Phys. Chem. Lett. 2013, 4, 2649-2657; Claridge, S. A., et al., Chem. Soc. Rev. 2013, 42, 2725-2745). However, ordering ligand to promote specific, spatially-resolved interactions with the environment (e.g. electrodes, optoelectronic active layers, analytes) is also a problem of growing importance for precisely registered integration into a functional device. Fundamentally, this requires spatial orientation information to be encoded in the ligand layer by displaying two or more different (e.g. wetting-orthogonal) surface chemistries in a controlled way. Related ligand chemistries have been developed for colloidal inorganic nanocrystals (e.g. construction of Janus particles), and have been a powerful enabler for oriented assembly of particles at interfaces including cell membranes and in solution-processed devices (Yi, Y. et al., Analyst 2016, 141, 3526-3539).
In principle, lying-down phases frequently used for noncovalent functionalization could represent a convenient means of presenting alternating stripes of orthogonal surface chemistries at very short length scales (<10 nm). Such a capability would be useful for structuring interfacial wetting (FIG. 1) for electronic, optoelectronic, sensing, and nanofluidic applications, in which feature sizes in that size regime are desirable, and are difficult to achieve via other interfacial patterning strategies (e.g. soft lithography) (Claridge, et al., 2013).
However, two key challenges arise in utilizing lying-down phases to pattern interfaces in this way. First, the noncovalent molecule-substrate interface in lying-down monolayers is not intrinsically robust toward removal or replacement of solvent, a frequent requirement for device fabrication or other sample processing (MacLeod, et al., 2014). This problem has begun to be addressed through strategies such as in situ polymerization of the ligand layer (e.g. topochemical photopolymerization of diynes) (Tahara, K., et al., ACS Nano 2014, 8, 8683-8694; Cui, D., et al., Chem. Comm. 2015, 51, 16510-3). Second, and less widely examined, are the challenges that arise in directing local wetting utilizing functional patterns that modulate interface dielectric near or at the molecular scale, particularly when using polar solvent on a nonpolar layered material interface (Bang, J. J., et al., J. Am. Chem. Soc. 2016, 138, 4448-4457). These challenges relate to both the behavior of functional groups in dimensionally confined high-dielectric/low-dielectric environments, and the behavior of liquids confined near an interface (Bain, C. D., et al., Langmuir 1989, 5, 1370-1378). The invention disclosed herein may provide a practical solution to those challenges.